McCain was the last senator to question Comey Thursday in Washington. Arizona's senior senator immediately addressed the Clinton investigation, asking the former FBI director to explain the difference between being able to reach a conclusion in that case but not in the ongoing Russia and Trump administration investigation.

Comey said the FBI completed its investigative work into Clinton and the two were "no where near the same place," at least not when he was heading the agency.

"I think that the American people have a whole lot of questions out there, particularly since you just emphasized the role that Russia played," McCain said. "Obviously she was a candidate for president so she was clearly involved in this whole situation."

"In respect to Secretary Clinton we investigated, a criminal investigation, in connection with her use of a personal email server," Comey said. "We have not announced, and there has been no predication to announce, whether the Russians may have coordinated with Secretary Clinton."

McCain continued to question how a conclusion was reached in one investigation going so far as to call it a "double standard."

"Both President Trump and former candidate Clinton are involved in the investigation yet one of them there's going to be no charges and the other one the investigation continues," McCain said.

The seven-minute exchange had many scratching their heads and at one point even Comey said "I'm a little confused senator."

Following the hearing a reporter asked Florida Sen. Marco Rubio about the "double standard," he said "I didn't follow that line of questioning very well."

After the tweet storm against him, McCain released a statement saying he got "the sense from Twitter than my line of questioning today went over people’s heads" and maybe he should not "stay up late watching the Diamondbacks night games."

He said he was trying to address the matter of whether or not Comey believed his interactions with the president constituted obstruction of justice.

"While I missed an opportunity in today’s hearing, I still believe this question is important, and I intend to submit it in writing to Mr. Comey for the record,” he said

Read McCain's statement in its entirety below:

I get the sense from Twitter that my line of questioning today went over people’s heads. Maybe going forward I shouldn’t stay up late watching the Diamondbacks night games.

What I was trying to get at was whether Mr. Comey believes that any of his interactions with the President rise to the level of obstruction of justice. In the case of Secretary Clinton’s emails, Mr. Comey was willing to step beyond his role as an investigator and state his belief about what ‘no reasonable prosecutor’ would conclude about the evidence. I wanted Mr. Comey to apply the same approach to the key question surrounding his interactions with President Trump—whether or not the President’s conduct constitutes obstruction of justice. While I missed an opportunity in today’s hearing, I still believe this question is important, and I intend to submit it in writing to Mr. Comey for the record.